Method of producing complex shapes cutouts holes cavities excavations and the like in a workpiece

ABSTRACT

An electrochemical method of producing a complex shape in a workpiece by utilizing a shaping tool supplied with an electrolytic solution as the cathode and the workpiece as the anode. A first cathode of a first simple geometric configuration is positioned in operative proximity with the workpiece and is used to electrochemically form a first cavity of simple geometric configuration in the workpiece. A cover is then placed over the first cavity and a second cathode of a second simple geometric shape is then placed in operative proximity with cover and workpiece. The second cathode is used to electrochemically form along a common axis an opening in the cover and a second cavity of simple geometric configuration in overlapping relation to the first cavity in the workpiece, whereupon, the cover is removed.

United States Patent [72] Inventors Karl-Georg Gunther [73] Assignee Siemens-Schuckertwerk Aktiengesellschaft Berlin, Germany [32] Priority Mar. 17, 1965 [33] Germany [31 396002 Continuation of application Ser. No. 534,833, Mar. 16, 1966, now abandoned. V

[54] METHOD OF PRODUCING COMPLEX SHAPES,

CUTOUTS, HOLES, CAVITIES, EXCAVATIONS AND THE LIKE IN A WORKPIECE 3 Claims, 18 Drawing Figs.

[52] U.S. Cl 204/143 M, 204/224 [51] Int. Cl 823p 1/00 [50] Field of Search 204/143, 143 M, 224; 219/69 R, 69 M, 69 D, 69 V, 69 S; 77/55 G; 83/635 [56] References Cited UNITED STATES PATENTS 2,612,793 10/1952 Timpner.... 77/55 G 3,120,482 2/1964 Williams 204/143 M X FOREIGN PATENTS 373,489 8/1959 Switzerland 204/143 Primary Examiner-John H. Mack Assistant Examiner-Neil A. Kaplan ABSTRACT: An electrochemical method of producing a complex shape in a workpiece by utilizing a shaping tool supplied with an electrolytic solution as the cathode and the workpiece as the anode. A first cathode of a first simple geometric configuration is positioned in operative proximity with the workpiece and is used to electrochemically form a first cavity of simple geometric configuration in the workpiece. A cover is then placed over the first cavity and a second cathode of a second simple geometric shape is then placed in operative proximity with cover and workpiece. The second cathode is used to electrochemically form along a common axis an opening in the cover and a second cavity of simple geometric configuration in overlapping relation to the first cavity in the workpiece, whereupon, the cover is removed.

PAIENTEDUBI 26 Ian SHEET 2 [1F 3 Fig.7b

Fig.6 b

Fig.5b

Fig.8

PATENTEDUET 26 I97! 3,616,351

SHEET 3 UP 3 Fig. 9 Fig. 10

Fig. H Fig. 12

METHOD OF PRODUCING COMPLEX SHAPES, CUTOU'IS, HOLES, CAVITIES, EXCAVATIONS AND THE LIKE IN A WORKPIECE This is a continuation of application Ser. No. 534,833 filed Mar 16, 1966, now abandoned.

The present invention relates to a method of and apparatus for producing complex shapes, cutouts, holes, cavities, excavations and the like in a workpiece. More particularly, the invention relates to an electrochemical method of and apparatus for producing complex shapes, cutouts, holes and the like in a workpiece.

In an electrochemical method of producing shapes, cutouts, holes and the like in highly refractory and wear-resistant workpieces, the workpiece functions as the anode and the cutting, gouging or drilling tool or the like functions as the cathode; an adjustable or variable DC voltage being applied between said anode and cathode. The tool has a conduit formed therethrough and a hydrous electrolyte solution flows through such conduit to the hole, cavity, excavation or the like in the workpiece. Charge transfer processes, which also occur in galvanic processes for electrolytic etching or polishing, produce dissolving of the workpiece in accordance with the feeding motion of the tool.

In the electrochemical method, the current magnitude is two or three times greater than that of the galvanic processes. This increases the speed of the removal or excavation of material from the workpiece to mm. per minute or more, depending upon the type and shape or the tool. For increased speed of excavation, the electrolyte solution must flow rapidly through the space between the tool and the workpiece. The electrolyte solution is thus supplied to the tool at a pressure of several atmospheres. The electrochemical method provides an engraving, excavation, cutout, hole, cavity or the like of any desired shape having any desired cross-sectional area.

In the electrochemical method of producing shapes, cutouts, holes and the like in a workpiece, the cathode must be in the shape of a negative of the desired configuration of the hole or the like. Furthermore, the high flow velocity of the electrolyte solution requires corrections in flow velocity to be made at the cathode. When a complex shape, cavity or the like is to be produced, it is therefore difficult to provide the required cathode, so that the electrochemical method is limited to producing simple or basic geometrical shapes or the like.

The principal object of the present invention is to provide a new and improved method of producing complex shapes, cutouts, holes, cavities, excavations and the like in a workpiece. The method of the present invention is an electrochemical method which does not require a cathode of complex configuration, but which produces a shape, cutout or the like of complex configuration with simplicity, accuracy, effectiveness and reliability.

In accordance with the present invention, an electrochemical method produces complex shapes, cavities and the like in a workpiece by utilizing a shaping tool as the cathode and the workpiece as the anode. A first cathode of a first simple geometric configuration is utilized to electrochemically form a first cavity of the first simple geometric configuration in the workpiece. The first cavity is covered with a removable cover. A second cathode of a second simple geometric configuration is utilized to electrochemically form a second cavity of the second simple geometric configuration in the removable cover and in partially overlapping relation with the first cavity in the workpiece under the removable cover to form with the first cavity a resultant cavity of complex configuration in the workpiece. Each of the first and second cavities is formed to a determined depth in the workpiece independent of the other, and the first and second cavities overlap each other to a determined extent. After the steps described, the cover is removed.

In order that the present invention may be readily carried into effect, it will now be described with reference to the accompanying drawings, wherein:

FIG. 1a is a sectional view and FIG. 1b a top plan ofa workpiece illustrating an initial step of a first example of the method of the present invention; FIGS. la and lb are hereinafter collectively designated as FIG. I, and an analogous designation is applied to each of the pairs of illustrations FIG. 2a, 2b, to FIG. 7a, 7b;

FIG. Zais a sectional view and a FIG. 2btop plan of the workpiece of a 1 illustrating a next following step of the b example of the method of the present invention;

FIG. 3a is a sectional view and FIG. 3b a top plan of the workpiece of FIG. 2 illustrating the last step of the first example of the method of the present invention;

FIG. 4 is a perspective view of the workpiece of FIG. 3 illustrating the result of the first example of the method of the present invention;

FIG. 5a is a side view and FIG. 5b a top plan of a workpiece illustrating an initial step of a second example of the method of the present invention;

FIG. 6a is a side view, partly in section, and FIG. 6b a top plan of the workpiece of FIG. 5 illustrating a next following step of the second example of the method of the present invention;

FIG. 7a is a side view, partly in section, and FIG. 7b a top plan of the workpiece of FIG. 6 illustrating the last step of the second example of the method of the present invention;

FIG. 8 is a perspective view of the workpiece of FIG. 7 illustrating the result of the second example of the method of the present invention;

FIG. 9 is a perspective view of the first cathode utilized in the first example ofthe method of the present invention;

FIG. 10 is a perspective view of the second cathode utilized in the first example of the method of the present invention;

FIG. I] is a perspective view of the first cathode utilized in the second example of the method of the present invention; and

FIG. 12 is a perspective view of the second cathode utilized in the second example of the method of the present invention.

The first example of the method of the present invention, illustrated in FIGS. 1 to 4, is for the production of a complex shape, cutout, hole, cavity, excavation or the like in a configuration having a spoonlike cross section, as shown in FIG. 4, in a metal workpiece. In FIG. laa workpiece II is supported as an anode on a supporting platform (not shown). In the first step of the method, the first cathode utilized in the method is a tool having a circular cross section (FIG. 9) which removes material in the electrochemical process, from the workpiece II to form a cylindrically shaped cutout, hole, cavity, excavation or the like 12. The cylindrically shaped cavity 12 is shown in FIG. I.

In the next step of the method shown in FIG. 2, a plate 13, which may comprise, for example, steel, having a thickness of 0.5 mm., is placed over the cavity 12. The first cathode is replaced by a second cathode which is a tool having an elongated cross section in the shape of an elongated rectangle with arcuate or semicircular ends replacing the short sides of the rectangle (FIG. 10).

In the last step of the method, the second cathode removes material, in the electrochemical process, from the plate 13 and from the workpiece II to form in each an elongated rectangularly shaped cross-sectioned cutout, hole, cavity, excavation or the like 14 having rounded arcuate or semicircular ends replacing the short sides of the rectangle. The rounded end elongated rectangularly shaped cross-sectioned cavity 14 is shown in FIG. 3.

As desired, the rounded end elongated rectangularly shaped cross-sectioned cavity 14 is produced adjacent to and extending from the cylindrically shaped cavity 12 in a manner whereby one end of said cavity 14 is lost due to the previous excavation of the cavity 12. The end result, as illustrated in FIG. 4, is a cavity, excavation, hole or the like 15 having a spoonlike cross section, as desired. In accordance with the method of the present invention, the complex excavation or the like 15 is produced with two cathodes of simple or basic geometrical cross-sectional configuration.

The second example of the method of the present invention, illustrated in FIGS. 5 to 8, is for the production of a complex shape, cutout, hole, cavity, excavation or the like in a configuration having an isosceles trapezoidlike cross section, as shown in FIG. 8, in a cube formed from a metal workpiece. in FIG. 5a, a workpiece 21 supported as an anode on a supporting platform (not shown). in the first step of the method, the first cathode utilized in the method is a tool having a square cross section (FIG. 11) which removes material, in the electrochemical process, from the workpiece 21 in the shape of eight cubes bordering on a ninth cube 23, which is left on an extending base or ledge portion 24. The cube 23 is shown in FIG. 5.

in the next step of the method, shown in FIG. 6, a tubular or cylindrical member 25 of metal or plastic material, for example, having an altitude or lateral or axial length equal to or greater than the width of the cube 23, is placed around said cube on the base portion 24 of the workpiece 21. A plate 26, which may comprise, for example, steel, having a thickness of 0.5 mm., is placed over the cube 23 on the upper rim of the cylindrical member 25. The first cathode is replaced by a second cathode which is a tool having an equilateral triangular cross section (H0. 12).

in the last step of the method, the second cathode is positioned with a base of its triangular cross section parallel to and spaced about one third of the altitude of the triangular cross section from the closest edge of the cube 23, as shown in FIG. 7, and removes material, in the electrochemical process, from the plate 26 and from the cube 23 to form in said plate an equilateral triangular-shaped cross-sectioned cutout, hole, cavity, excavation or the like 19 and to form in said cube an isosceles trapezoid shaped cross-sectioned cutout, hole, cavity, excavation or the like 27.

As desired, the isosceles trapezoid cross-sectioned cavity 27 is produced in the cube 23 extending from an edge of said cube and opening on a side surface of said cube to form an object having the configuration shown in FIG. 8 as the end result. in accordance with the method of the present invention, the

complex shaped object 28 is produced with two cathodes of basic geometrical cross-sectional configuration.

While the invention has been described by means of specific examples and in a specific embodiment. I do not wish to be limited thereto, for obvious modifications will occur to those skilled in the an without departing from the spirit and scope of the invention.

We claim:

1. An electrochemical method of producing complex shapes, cavities and the like in a workpiece by utilizing a shaping tool as a cathode and the workpiece as an anode, the method comprising the steps of positioning a first cathode of a first simple geometric configuration into operative proximity with the workpiece; passing an electrolyte solution between the first cathode and the workpiece so as to be in contact therewith; passing a current through the first cathode, the electrolyte solution and the workpiece to electrochemically form a first cavity of the first simple geometric configuration in the workpiece; covering the first cavity and at least a portion of the workpiece adjacent said first cavity with a removable cover, positioning a second cathode of a second simple geometric shape into operative proximity with the cover and the workpiece; passing the electrolyte solution between the second cathode and workpiece so as to be in contact therewith; passing a current through the second cathode, the electrolyte solution, and the workpiece to electrochemically form along an axis the second cavity of the second simple geometric configuration in partially overlapping relation to the first cavity in the workpiece; and removing the cover.

2. An electrochemical method as claimed in claim 1, further comprising the steps of positioning a cover support around at least a portion of said workpiece and removably covering said first cavity by removably covering said cover support with a removable cover.

3. An electrochemical method as claimed in claim I,

wherein said second cavity is formed in said workpiece to a depth smaller than that of the first cavity.

i i t i 2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, ,35 Dated October 9 InvmmrmmgR -GEOR GUNTHER, GUSTAV STARK and KLAUS OTTO It is certified that: error appears in the above-identified patent and that said Letters Patent are hereby corrected u shown below:

In the needing the German priority number should read as follows: --S 96002-- Signed and sealed this 28th day of March 1972.

SEAL) \ttest:

EDWARD M.F'LETCHER,JR. ROBERT GOT'I'SCHALK tteating Officer Commissionerof Patents 

2. An electrochemical method as claimed in claim 1, further comprising the steps of positioning a cover support around at least a portion of said workpiece and removably covering said first cavity by removably covering said cover support with a removable cover.
 3. An electrochemical method as claimed in claim 1, wherein said second cavity is formed in said workpiece to a depth smaller than that of the first cavity. 